The type of vegetation for a green roof can be loosely classified in these categories:
General Green Roof Types for Small Green Roofs
Extensive – lightweight – sedum blanket or mat solutions – below 90kg/m2
Sedum plant species are well adapted to their use within extensive and semi-extensive green roofs. They are very drought tolerant, normally able to withstand climate extremes and are regularly grown in or on shallow substrate layers.
- There are solutions that are marketed that can be installed with a saturated weight of 55kg/m2
- We would always recommend that you try wherever possible to install with at least 80mm of substrate (if not more – with the blanket or mat this would give a saturated weight of approximately 120kg/m2
- low maintenance.
Extensive – sedum and herb roofs using seeds plug plants and or turfs/blankets
Biodiverse roofs are created primarily for biodiversity purposes and can aim to create or enhance habitats for insects, birds, plants and animals. This includes includes the “Brown Roof” which is not purposefully planted but instead the growing medium is chosen and installed to allow indigenous plant species to naturally colonise the roof over time.
- This is the approach we recommend – depending on the depth of substrate the saturated weight would between 120 – 250kg/m2
- low maintenance, may need some irrigation in long periods of drought.
Semi-intensive green roofs – herbs, food, ornamental flowers
These are more traditional garden type green roofs.
- Generally an semi-intensive green roof needs regular maintenance – saturated weight of between 170 – 300kg/m2
- medium maintenance with regular irrigation through dry periods.